Converter appliance capacitor assembly

ABSTRACT

The invention relates to a capacitor module for a converter. The capacitor module contains a capacitor which can be fastened to a base frame or to a cooling body by means of lateral, mechanical holding devices. In addition, the capacitor comprises at least one additional mechanical holding device for fastening at least one electronic terminal of the converter and of at least one measuring sensor, especially of a current transformer and/or of a voltage transformer. The inventive capacitor module makes it possible to realize a construction of a converter which is compact and has a reduced weight.

DESCRIPTION

The invention relates to a converter appliance capacitor assembly whichhas at least one capacitor and can be attached by means of sidemechanical holders to a base frame of the converter appliance or to aheat sink.

A capacitor assembly for a converter appliance has been proposed inGerman patent application P 198 13 365.0, in which a central, metallicmultifunction housing part, which is connected directly to the heat sinkof the power semiconductors, is connected to the capacitors such that itmakes thermal contact. The driver circuits for the power semiconductorsand the control and regulating arrangement of the converter applianceare located above the capacitors. These components are connected to themultifunction housing part via attachment devices required for thispurpose. The multifunction housing part can be designed with or withouta power busbar system.

A modular system for forming converter appliances of different power andwith different types of cooling is known from DE 196 28 549 A1. In thiscase, a large number of individual capacitors are combined to formcapacitor groups and are attached via holding plates to the cooler ofthe converter appliance.

A circuit arrangement for operation of at least one battery-poweredelectric motor in an industrial truck is known from DE 44 12 407 A1. Inthis case, at least one row of capacitors is arranged on a mountingbody, which is connected to the cooler of a converter appliance.

A power converter having a capacitor assembly is known from U.S. Pat.No. 5,729,450. In this case, a large number of individual capacitors areattached by means of side holding plates to the frame of the converter.The electrical connections arranged on the front faces of the capacitorsare connected to busbars.

The invention is based on the object of specifying a converter appliancecapacitor assembly, which allows the converter appliance to have anextremely compact design.

This object is achieved by a converter appliance capacitor assemblywhich is designed as a load-bearing component of the converter applianceand has at least one front or side mechanical electrical connection andmeasurement sensor holder for making contact with external powerconnections, such as an electrical power supply and load connections.

The advantages which can be achieved by the invention are, inparticular, that the proposed converter appliance capacitor assemblymakes it possible to design a converter appliance such that space issaved, the weight is reduced and costs are reduced. Since the converterappliance capacitor assembly is itself designed as the load-bearingcomponent of the converter appliance, there is no need whatsoever forthe mechanical supporting and auxiliary frames which are normallygenerally used for converter appliances. A further advantage is that theconverter appliance capacitor assembly can be disassembled forrecycling.

One advantageous refinement of the invention is for at least oneelectronic circuit—preferably a drive circuit for powersemiconductors—to be attached to the front mechanical holder. Thisembodiment assists the idea of the invention of allowing the capacitorassembly to be designed as compactly as possible.

The mechanical holder can be arranged at the front or side with respectto the capacitor. Depending on the spatial requirements, it may in thiscase be advantageous for a number of individual holders to be providedat the side of the capacitor. This means that the converter appliancecapacitor assembly according to the invention can be used for a largenumber of spatial requirements.

The invention will be explained in more detail in the following textwith reference to the exemplary embodiments which are illustrated in thedrawing, in which:

FIG. 1 shows a perspective view of a capacitor assembly according to theinvention;

FIG. 2 shows a view of the front face of a converter appliance fittedwith the capacitor assembly according to the invention;

FIG. 3 shows a view of a side surface of a converter appliance fittedwith the capacitor assembly according to the invention, and

FIG. 4 shows a perspective view of a further embodiment of the capacitorassembly according to the invention.

FIG. 1 shows a perspective view of a capacitor assembly. A cubic orcuboid capacitor 1 can be seen, which is connected to side mechanicalholders 2, 3 on two opposite side surfaces. The capacitor may beintegral, but it is also possible to combine a number of individualcapacitors of smaller capacitance to form the capacitor with the desiredcapacitance. The two side mechanical holders 2, 3 are used for mountingthe capacitor assembly on the base frame 4, for example on a heat sink(see item 12 in FIGS. 2 and 3). The capacitor 1 has a further, frontmechanical holder 5, which extends on a face—from now on referred to asthe front face—located between the mechanical holders 2, 3.

The front mechanical holder 5 of the capacitor assembly is used forattachment of electrical connections 6 (AC voltage connections, DCvoltage connections) of the converter appliance and for attachment ofmeasurement sensors in particular of three current transformers 7 andone voltage transformer 8. Furthermore, a number of electronic circuits9 are attached to the front mechanical holder 5. These electroniccircuits 9 are drive circuits for the power semiconductors of theconverter appliance.

A further, flat electronic circuit 10 is attached to the top face of thecapacitor assembly or of the capacitor 1, this being the control andregulating device for driving the power semiconductors.

FIG. 2 shows a view of the front face of a converter appliance fittedwith the capacitor assembly. This shows that the capacitor 1 is mountedvia the two side mechanical holders 2, 3 on a heat sink 12 to which alarge number of power semiconductors 11, which are arranged side byside, are fitted. In the exemplary embodiment, this is a heat sink 12which is fitted with cooling plates 13 and is suitable for air cooling.Liquid heat sinks can, of course, also be used.

The electrical connections 6 and current transformers 7 mounted on thefront mechanical holder 5 are freely accessible on their top face inorder to make contact with external power connections (electrical powersupply, load connections), normally cable connections, and, on theirbottom face, make contact with connections of a busbar system 14 withinthe appliance. The busbar system 14 provides the electrical connectionsfor the individual power semiconductors 11 and, via a capacitorconnection 15 (see FIG. 3) at the rear, the electrical connections forthe capacitor 1.

FIG. 3 shows a view of a side surface of a converter appliance fittedwith the capacitor assembly. This shows the heat sink 12 with coolingplates 13, the power semiconductors 11 mounted in two rows on the heatsink 12, the capacitor 11 connected to the heat sink 12 via the sidemechanical holders 2, 3, the front mechanical holder 5 with a currenttransformer 7 attached to it, the busbar system 14 and the rearcapacitor connection 15. The side mechanical holder 3 has been removedin order to make it possible to see into the converter appliance.

FIG. 4 shows an embodiment of the capacitor assembly according to theinvention, modified from that in FIGS. 1 to 3. In this case, twoindividual holders 5′ are provided instead of the integral front holder5 as shown in FIGS. 1 to 3. These are also used for accommodating theelectrical connections 6 of measurement sensors, such as currenttransformers 7, and a voltage transformer. Furthermore, there areelectronic circuits 9 in the region of these individual holders 5′.

List of reference symbols

1 Capacitor

2 Side mechanical holder

3 Side mechanical holder

4 Base frame

5 Front mechanical holder

6 Electrical connection

7 Current transformer

8 Voltage transformer

9 Electronic circuit (drive circuit for power semiconductors)

10 Electronic circuit (control and regulating device)

11 Power semiconductor

12 Heat sink

13 Cooling plates

14 Busbar system

15 Capacitor connection

What is claimed is:
 1. A capacitor assembly for a converter appliance,comprising: a base unit comprising a base frame or heat sink; acapacitor having a front, a back, and two sides; two side mechanicalholders for mounting the capacitor to the base unit, one side mechanicalholder disposed on and connected to each side of the capacitor; at leastone electrical connector for connection to an external circuit; at leastone measurement sensor; and a front mechanical holder disposed at thefront of the capacitor for attachment of the at least one electricalconnector and measurement sensor, wherein the capacitor assembly isdesigned as a load-bearing component of the converter appliance.
 2. Thecapacitor assembly as claimed in claim 1, further comprising one or moreelectronic power semiconductor drive circuits attached to the frontmechanical holder.
 3. The capacitor assembly as claimed in claim 1,wherein the capacitor has a top surface and further comprising a powersemiconductor electronic control circuit attached to the top surface ofthe capacitor.
 4. The capacitor assembly as claimed in claim 1, whereinthe at least one measurement sensors comprise one or more currenttransformers.
 5. The capacitor assembly as claimed in claim 1, whereinthe at least one measurement sensors comprise a voltage transformer. 6.The capacitor assembly as claimed in claim 1, further comprisingelectrical connections on the back of the capacitor for connection toone or more busbars.
 7. The capacitor assembly as claimed in claim 1,wherein the capacitor comprises a plurality of individual capacitors. 8.The capacitor assembly as claimed in claim 1, wherein the sidemechanical holders comprise flat plates positioned substantiallyperpendicular to the base unit.
 9. A converter appliance comprising: acapacitor assembly comprising: a base unit comprising a heat sink; acapacitor having a front, a back, and two sides; a front mechanicalholder positioned at the front of the capacitor for attachment ofelectrical power connections; and two side mechanical holders formounting the capacitor to the base unit, one side mechanical holderdisposed on and connected to each side of the capacitor; and a pluralityof electrical connections on the back of the capacitor; a plurality ofpower semiconductors connected to the heat sink; and a plurality ofbusbars connected to the power semiconductors and the electricalconnections on the back of the capacitor.
 10. The converter appliance asclaimed in claim 9, further comprising one or more electronic drivecircuits attached to the front mechanical holder for driving the powersemiconductors.
 11. The converter appliance as claimed in claim 9,further comprising one or more measurement sensors attached to the frontmechanical holder.
 12. The converter appliance as claimed in claim 9,wherein the capacitor comprises a plurality of individual capacitors.13. The converter appliance as claimed in claim 9, wherein the sidemechanical holders comprise flat plates positioned substantiallyperpendicular to the base unit.